In a 6-to-5 vote, San Francisco’s Board of Supervisors voted Tuesday to ban public nudity – specifically, exposing one’s genitals on streets and on public transit. In other words, no bare buns on the BART.

Nudists could be fined $100 for a first-time offense; rebel nudists found naked a third time within a year will be fined $500 and could face up to a year in jail.

Exceptions to the ban: Children under five years and nudists in parades, fairs or festivals held under a city permit.

The ordinance was introduced by Supervisor Scott Wiener, who said he had heard increasing complaints from residents in San Francisco’s traditionally gay Castro District about a roaming band of increasingly bold naked men, the AP reported.

(Among the complaints: Men engaging in public sex, men charging tourists for pictures, and men walking around near Harvey Milk Elementary School, the San Francisco Chronicle reported.)

At Tuesday’s meeting, supervisors who opposed the nudity ban suggested that being naked could be a form of public expression. Supervisor David Campos argued that the police should spend their time fighting violent crime, the Chronicle reported.

The ban won’t go into effect until Feb. 1 – after another vote by the Board of Supervisors and the mayor’s approval.

Nudists filed a suit last week against the city and county of San Francisco.